Self Study: Trig leveling
Problem (1)
A TSI is set up 5.41' over point Q whose elevation is 745.39'. The following readings are taken:
| Point | Horizontal angle |
Vertical angle |
Slope distance |
| 101 | 0°00'00" | 4°24'10" | 145.25' |
| 102 | 39°56'15" | -06°00'25" | 89.32' |
| 103 | 79°05'45" | -02°58'30" | 118.95' |
The reflector height in each case was 5.64'. The instrument and reflector heights were measured with the same cloth tape.
What are the horizontal distances to and elevations of the observed points? Compute values to 0.01'.
Problem (2)
A TSI is set up over the SW corner of a property. The TSI height is 5.73' above the corner, measured with a fiberglass tape. The elevation of the top nut on a fire hydrant (FH) across the street is 827.43'.
From the TSI, the following readings are taken
| Point | Reflector Height1 |
Slope distance |
Horizontal angle |
Zenith angle |
| FH | 5.00 | 84.39' | 0°00'00" | 95°30'45" |
| NW | 6.25 | 194.48' | 44°51'55" | 87°05'35" |
| NE | 6.25 | 240.68' | 80°56'30" | 85°48'05" |
| SE | 7.50 | 142.02' | 134°51'35" | 92°23'50" |
1Measured with the same fiberglass tape.
What are the elevations of the four property corners? Compute to 0.01' to minimize rounding error.